The synthesis of the myelin basic proteins will be examined in several in vitro protein synthesizing systems. Further studies will be devoted to determining the sequence of molecular events which occur from the biosynthesis of the basic proteins to their assembly into the membrane. Work in our laboratory indicates that the two major myelin basic proteins are synthesized on free polyribosomes in mouse brain. We propose to extend these studies, using immunochemical methods, to determine the subcellular site of synthesis of all four forms of the myelin basic proteins. Kinetic and inhibitor studies will be used to determine whether a metabolic relationship exists among the four forms of the basic protein. In addition, an effort will be made to determine whether any or all of the myelin basic proteins are synthesized as precursors and, if so, the mechanism(s) by which they are processed.